Castillo, a first-round selection, is quickly coming into his own. For the third week, Castillo will start, as he's already leapfrogged Igor Olshansky, last year's second-round pick.

It's an impressive feat. And it's mostly because of Castillo's feet ---- and mind.

"He's making very good progress, as you might well expect from a Northwestern graduate,'' coach Marty Schottenheimer said. "He understands leverage and knows when he's got a guy off-balance.''

But speed and smarts only gets one so far. And so far, it's gotten Castillo on the verge of his first NFL sack ---- not slap, but sack.

Castillo's right mitt has already found the helmets of Dallas quarterback Drew Bledsoe and the Giants' Eli Manning. Castillo could hear today whether the NFL will dock him for smacking Manning; he avoided a fine for touching Bledsoe.

"It drives me crazy,'' Castillo said of his inadvertent contact which has drawn two flags and, on Sunday, wiped out a Drayton Florence touchdown off an interception. "I'm hoping (I go) 0-for-2; it would be nice to get out of those two fines because I don't want to throw that money away.''

It's another pocket Castillo wants to explore. But he's just missed corralling a rival quarterback, although he has nine pressures.

"I've always been athletic and I've always been big, but I'm no longer stronger than the guy in front of me,'' the 6-foot-3, 303-pound Castillo said. "It's a battle now. I'm close to winning and I'm getting around the quarterback but I haven't been able to finish that last little hump.''

There were other obstacles in training camp. First, he was moved from tackle to end ---- "I thought I was going to back up Jamal Williams,'' Castillo said ---- and leg injuries derailed his playing time in the exhibition games.

But he's made up ground fast, and on Sunday he squares off against the world champion Patriots ---- the same team that won Super Bowl XXXIX as Castillo and his Northwestern buddies watched on TV.

"It's amazing because you were sitting there in college or high school, watching these guys play,'' said Castillo, who has four tackles. "Now to be out there playing them and trying to bring them down is something.''

The Chargers speculate they have something keen in Castillo. Pass-rushers are like home-run hitters ---- they are tough to find and a cherished part of any team.

"He's very athletic for a 300-pound guy,'' Schottenheimer said.

With Castillo and Shawne Merriman, the team's other first-round pick, the Chargers hope they've bagged two big hitters.

Castillo's play is keeping Olshansky on the bench. Word out of Chargers amp is that Castillo provides a better pass rush than Olshansky. But I would like to see a front line of Olshansky, Castillo, and Williams.